JP5294116B2 - Treatment method of activated concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating activated concrete which treats the activated concrete both efficiently and economically. <P>SOLUTION: Ground products S of the activated concrete 1 obtained in a pulverization process 2 are grouped by prescribed particle diameter ranges and are treated by setting the treatment times for a washing process 3 and a solid-liquid separation process 4 according to each of the grouped ground products S. Moreover, a recovery process 5 includes a noncritical nuclide recovery process 5a for recovering noncritical nuclides in a treatment liquid W' by depositing them and a critical nuclide recovery process 5b for recovering critical nuclides in the treatment liquid W' by depositing them after the noncritical nuclide recovery process 5a. Furthermore, the ground products S obtained in the pulverization process 2 are grouped into fine ground products S1 of fine particles and normal ground products S2, which are treated in the washing process 3 and the solid-liquid separation process 4, and the fine ground products S1 are poured into the treatment liquid W' in a process before the treatment liquid W' separated from the normal ground products S2' is treated in the noncritical nuclide recovery process 5a to remove critical nuclides from the fine ground products S1. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for treating activated concrete, in which a determined nuclide is removed from activated concrete and the activated concrete is processed.

  2. Description of the Related Art Conventionally, in a nuclear facility such as a nuclear power plant, a structural frame is constructed of concrete because it has sufficient strength and is excellent in radiation shielding.

  On the other hand, since the concrete of such nuclear facilities is exposed to radiation and activated, it is necessary to store and manage it as radioactive waste when reconstructing the facility. And even though activated concrete is about 1% of the total concrete, for example, there is a problem that it takes a great deal of cost to store and manage it. It is requested to be.

  On the other hand, the inventors of the present application determine the pulverized product by pulverizing the activated concrete, and washing the pulverized product of the activated concrete obtained by the pulverizing step with a treatment liquid (cleaning solution) such as nitric acid. Neutralizing the cleaning process that chemically separates the nuclide (target element), the solid-liquid separation process that performs solid-liquid separation after the cleaning process, and the treatment liquid that is separated from the solid content (crushed material) in the solid-liquid separation process Has proposed a method for treating activated concrete comprising a recovery step of precipitating and recovering the determined nuclide in the treatment liquid (see, for example, Patent Document 1). By treating the activated concrete (waste concrete) with this activated concrete treatment method, the volume of the activated concrete can be reduced and most of it can be handled as general waste, greatly increasing the processing costs (disposal costs). Can be reduced.

Japanese Patent Laid-Open No. 2002-341088

  However, in the above-described activation concrete processing method, the cleaning step of removing the determined nuclide from the pulverized product obtained in the pulverization step, and the treatment liquid containing the determined nuclide and the pulverized product (solid content) are separated after the cleaning step. In the solid-liquid separation step, all pulverized products having different particle sizes are processed at the same time, so that there is a problem that the time and energy loss required for the processing are large. That is, the pulverized product with a small particle size and the pulverized product with a large particle size are different in the processing time required for removing the determined nuclide in the washing process or separating the processing liquid and the solid content in the solid-liquid separation process. In the washing step, the pulverized product having a small particle size can be processed in a shorter time than the pulverized product having a large particle size. For this reason, when pulverized products having different particle diameters are processed at the same time in the washing step and the solid-liquid separation step as in the past, depending on the particle size of the pulverized product (maximum diameter or minimum diameter of the pulverized product) that requires the most processing time. The processing time must be set, and the time and energy loss required for processing increase.

  On the other hand, in the recovery step, sodium hydroxide is added to neutralize the treatment solution exhibiting strong acidity by using nitric acid or the like in the washing step. Thereby, the determined nuclide (determined nuclide dissolved in the treatment liquid) in the treatment liquid is precipitated and recovered as a hydroxide. However, for example, non-determined nuclides such as iron and aluminum contained in activated concrete cement and aggregate are also dissolved in the treatment liquid after the cleaning process. Non-determined nuclides will also precipitate with the determined nuclides. And even though most of the precipitates obtained by neutralization are non-determined nuclide precipitates, it is necessary to dispose of all the precipitates as radioactive waste (storage management), which is one factor that increases the processing costs. It was.

  In addition, the coarse aggregate contained in activated concrete can be reduced in weight from the original weight to about 1% as solids including the determined nuclide by treating it with nitric acid in the washing process. It is. On the other hand, the finely pulverized product (fine particles) generated in the pulverization step, particularly the fine pulverized product having a particle size of less than 0.5 mm, is difficult to separate and recover in the solid-liquid separation step after being processed in the washing step. Therefore, it is being considered to dispose of it as radioactive waste. However, since this finely pulverized material accounts for several percent of the weight before pulverization, if it is disposed as it is, the amount of radioactive waste and, consequently, an increase in processing costs will be caused. For this reason, there has been a strong demand for a method for removing the determined nuclide from the finely pulverized product.

  An object of this invention is to provide the processing method of activated concrete which can process activated concrete efficiently and economically in view of the said situation.

  In order to achieve the above object, the present invention provides the following means.

  The activation concrete processing method according to claim 1, wherein the activated concrete is pulverized, and the activated concrete obtained in the pulverization step is washed with a treatment liquid to determine the determined nuclide from the pulverized product. Of the activated concrete comprising: a cleaning step to be removed; a solid-liquid separation step for separating the pulverized material after the cleaning step and the treatment liquid; and a recovery step for collecting the determined nuclide from the treatment liquid separated in the solid-liquid separation step. In the processing method, the pulverized product obtained in the pulverization step is grouped for each predetermined particle size range, and the processing time of the washing step and the solid-liquid separation step is set for each grouped pulverized product. It is characterized by being processed.

  The method for treating activated concrete according to claim 2 is the method for treating activated concrete according to claim 1, wherein the recovery step precipitates and collects nondetermined nuclides in the treatment liquid, and And a determined nuclide recovery step of precipitating and recovering the determined nuclide in the treatment liquid after the non-determined nuclide recovery step.

  The activated concrete treatment method according to claim 3 is the activated concrete treatment method according to claim 2, wherein in the non-determined nuclide recovery step, ammonia water is added to the treatment solution to neutralize the non-determined nuclide. In the determined nuclide recovery step, the determined nuclide is precipitated by adding sodium hydroxide to the treatment liquid to neutralize the solution.

  The activation concrete treatment method according to claim 4 is the activation concrete treatment method according to claim 2 or claim 3, wherein the pulverized material obtained in the pulverization step is divided into finely pulverized material and the pulverized material. The normal pulverized product other than the finely pulverized product is grouped, the normal pulverized product is processed in the washing step and the solid-liquid separation step, and the treatment liquid separated from the normal pulverized product is treated as the non-determined nuclide in the recovery step. Before the treatment in the recovery step, the finely pulverized product is introduced into the treatment liquid, and the determined nuclide is removed from the finely pulverized product.

  In the method for treating activated concrete according to claim 1, the pulverized material obtained in the pulverization step is grouped for each predetermined particle size range, and each group is processed in the washing step and the solid-liquid separation step. Yes. The pulverized product of each group can be processed efficiently by setting the processing time for each group because the required processing time for washing and solid-liquid separation differs depending on the particle size of each group. As a result, the time and energy required for the treatment can be reduced and the activated concrete can be treated efficiently and economically as compared with the case where the pulverized products having different particle sizes are treated at the same time as in the past. Become.

  Further, in the method for treating activated concrete according to claim 2, the recovery step is divided into a non-determined nuclide recovery step and a determined nuclide recovery step, and for the treatment liquid exhibiting strong acidity by using nitric acid or the like in the washing step, In the non-determined nuclide recovery step, neutralization is performed using, for example, aqueous ammonia. Thereby, only non-determining nuclides such as iron and aluminum in the treatment liquid can be precipitated and recovered as hydroxides. Then, the treatment liquid from which the non-determined nuclides have been removed is further neutralized using sodium hydroxide or the like, so that the determinant nuclides such as cobalt (Co) and europium (Eu) remaining in the treatment liquid are removed. It can be recovered by precipitation as a hydroxide. In this way, the precipitate of non-determined nuclides and the precipitate containing a large amount of determinable nuclides are separately precipitated and collected, thereby neutralizing the conventional treatment liquid and simultaneously collecting the non-determined nuclides and the determinable nuclides to collect them. Compared with the case where it carries out, the deposit which contains many determination nuclides can be obtained after a determination nuclide collection | recovery process, and it becomes possible to reduce processing cost significantly. Therefore, it becomes possible to process activated concrete more efficiently and more economically.

  Further, in the method for treating activated concrete according to claim 3, the non-determined nuclide recovery step is performed by neutralizing the treatment liquid using ammonia water in the non-determined nuclide recovery step and sodium hydroxide in the non-determined nuclide recovery step. In this way, it is possible to leave the determined nuclide in the processing liquid and to reliably collect and remove the non-determined nuclide as a hydroxide, and to remove the determined nuclide remaining in the processing liquid after the non-determined nuclide recovery process in the determined nuclide recovery process. It is possible to reliably recover and remove it as a hydroxide.

  Further, in the method for treating activated concrete according to claim 4, before the nondetermined nuclide recovery step is performed on the treatment liquid in which the normal pulverized product is processed in the washing step and the solid-liquid separation step and the normal pulverized product is separated. At a stage (ie before neutralization), the finely pulverized product is charged. Since the particle size of the finely pulverized product is small by adding it to the treatment liquid before the non-determined nuclide recovery step in this way, it is possible to remove the determined nuclide from the finely pulverized product stably in a short time. After removing the determined nuclide from the finely pulverized product, the non-determined nuclide recovery step and the determined nuclide recovery step are performed, and the precipitate of the non-determined nuclide that does not contain the determined nuclide and the precipitate that contains a large amount of the determined nuclide are collected individually. By doing so, it becomes possible to reliably process the finely pulverized product together with the normal pulverized product. Thereby, it becomes possible to process activated concrete more efficiently and economically.

It is a flowchart which shows the processing method of the activated concrete which concerns on one Embodiment of this invention. It is a figure which shows the difference of the radioactive radioactive substance density | concentration in concrete by a neutron flux fluctuation | variation, and is a figure which shows the relationship between concrete depth and radioactive radioactive substance concentration.

  Hereinafter, with reference to FIG.1 and FIG.2, the processing method of the activated concrete which concerns on one Embodiment of this invention is demonstrated. The present embodiment relates to a method for treating activated concrete generated as solid waste in accordance with, for example, renovation of a nuclear facility such as a nuclear power plant.

  As shown in FIG. 1, the activated concrete processing method of the present embodiment includes a pulverization step 2 for pulverizing the activated concrete (waste concrete lump) 1 generated in a nuclear facility, and the radiation obtained in the pulverization step 2. Washing process 3 in which the crushed concrete S is washed with the treatment liquid (cleaning liquid W) to remove (extract) the determined nuclide from the crushed material S, and the solid content after the washing process 3 (crushed product S ′) and the treatment liquid The solid-liquid separation step 4 for separating W ′, the recovery step 5 for recovering the determined nuclide from the treatment liquid W ′ separated in the solid-liquid separation step 4, and the solid content S ′ separated in the solid-liquid separation step 4 are dried. And a drying process 6.

  In the pulverization step 2, the activated concrete 1 is pulverized using a pulverizer so as to have a particle size of, for example, 10 mm or less. At this time, it is desirable to pulverize the activated concrete 1 in a flake form so that a pulverized product S having a surface area as large as possible can be obtained by using a pulverizer such as a roll crusher.

  In the present embodiment, the pulverized product S obtained in the pulverization step 2 using a sieve or the like is grouped into a finely pulverized product S1 having a particle size of less than 0.5 mm and a normal pulverized product S2 of 0.5 mm or more. (The pulverized product S is grouped into a finely pulverized product S1 and a normal pulverized product S2 other than the finely pulverized product S1). Furthermore, the normal pulverized product S2 is grouped into, for example, 0.5 to 2 mm, 2 mm to 4 mm, 4 mm to 7 mm, and 7 mm to 10 mm. Thus, in this embodiment, the pulverized product S obtained in the pulverization step 2 is divided into five groups for each predetermined particle size range.

Next, the four groups of pulverized products S of the normal pulverized product S2 are washed in the cleaning step 3. Here, as shown in FIG. 2, the activated concrete 1 of the biological shield of the nuclear power plant that is currently predicted has a very small amount of radionuclides, that is, ⁶⁰ Co, ^{152 which} is a determinant for all radionuclides. If Eu and ¹⁵⁴ Eu are removed, all of the activated concrete (waste concrete) 1 can be handled as general waste. For this reason, in the present embodiment, Co (cobalt) and Eu (europium) are used as determinants, and this is described as being separated and removed from the pulverized product S.

  In the activation concrete processing method of this embodiment, when the crushed material S2 is washed in the washing step 3, the washing is performed for each group. That is, first, the first group of normal pulverized material S2 is charged into the cleaning tank, and the pretreated liquid W is supplied to the cleaning tank, and Co and Eu present in the first group of normal pulverized material S2 are supplied. Is chemically separated (extracted) by the treatment liquid W. Thus, at the stage where the first pulverized product S2 of the first group is washed, the ordinary pulverized product (solid content S2 ') in the washing tank and the treatment liquid W' are sent to the solid-liquid separation step 4 of the next step. Then, the normal pulverized material S2 of the second group, the normal pulverized material S2 of the third group, and the normal pulverized material S2 of the fourth group are sequentially washed in the cleaning step 3 in the same manner as the normal pulverized material S2 of the first group. The nuclide is removed from the group's normal pulverized product S2.

  At this time, for example, a pH adjusting agent and a chelating agent are used for the treatment liquid W, and an acidic aqueous solution such as nitric acid, perchloric acid, or ammonium nitrate is used for the pH adjusting agent. Further, as the chelating agent, for example, pyrrolidine-N-dithiocarboxylic acid ammonium salt (APDC) is used as a compound that forms a chelate compound with Co, and as a compound that forms a chelate compound with Eu, for example, trifluoroacenoylacetone (TTA). Is used.

  Here, when the normal pulverized product S2 is washed in the cleaning process as described above, the normal pulverized product S2 of each group has a different particle size (particle size range) for each group. The required processing time is different. For this reason, in this embodiment, processing time is set for every group with respect to the normal pulverized material S2 divided into groups for each particle size range. Thereby, the normal pulverized product S2 of each group is subjected to a cleaning process for a necessary processing time set according to the particle size of each group, and the determined nuclide is reliably removed for each group. Therefore, in the cleaning process 3 of the present embodiment, the cleaning process is efficiently performed while reducing the time and energy required for the processing as compared with the case where the pulverized material S having different particle diameters is simultaneously processed as in the conventional case.

  Moreover, the normal pulverized product S2 ′ and the treatment liquid W ′ of each group sequentially sent to the solid-liquid separation step 4 after the washing step 3 are solid-liquid separated in the solid-liquid separation step 4 using a centrifugal separation method, The normal pulverized product S2 ′, which is a solid content, is returned again to the cleaning step 3 as necessary, and the processing liquid W ′, which is a liquid content, is sent to the recovery step 5. When the normal pulverized product S2 ′ and the treatment liquid W ′ of each group are processed in the solid-liquid separation process 4, the normal pulverized product S2 ′ sequentially sent together with the treatment liquid W ′ from the cleaning process 3 is Since the particle size (particle size range) is different for each group, the required processing time required for solid-liquid separation is different for each group. For this reason, in this embodiment, the processing time is set for each group for the normal pulverized product S2 'and the processing liquid W' grouped for each particle size range. As a result, the normal pulverized product S2 'and the processing liquid W' of each group are processed for a required processing time set according to the particle size of each group, and are reliably solid-liquid separated for each group. Therefore, in the solid-liquid separation step 4 of the present embodiment, compared with the conventional case where the pulverized product S having different particle diameters is processed at the same time, the time and energy required for the processing are reduced and the solid-liquid separation processing is efficiently performed. Is done.

  The strongly acidic process liquid W ′ sequentially sent to the recovery process 5 after the solid-liquid separation process 4 is subjected to a process of recovering Co and Eu from the process liquid W ′ in the recovery process 5. At this time, by performing a cleaning process on the normal pulverized material S2 using a processing liquid W such as nitric acid in the cleaning process 3, for example, a metal such as iron or aluminum contained in the cement of the activated concrete 1 or the aggregate The component (non-determined nuclide) is also dissolved in the processing liquid W ′ together with Co and Eu. For this reason, when sodium hydroxide is added and neutralized with respect to the treatment liquid W ′ sent to the recovery step 5, not only the determined nuclides of Co and Eu in the treatment liquid W ′ but also iron (Fe) and Nondetermined nuclides such as aluminum (Al) also precipitate as hydrates.

  On the other hand, in the present embodiment, the recovery process 5 is divided into a non-determined nuclide recovery process 5a and a determined nuclide recovery process 5b, and ammonia water is first added to the non-determined nuclide recovery process 5a with respect to the treatment liquid W ′ exhibiting strong acidity. Use to neutralize. At this time, by adding ammonia water to the treatment liquid W ′ and neutralizing the pH of the treatment liquid W ′ to a weak acid region of 3 to 5, Co and Eu are dissolved in the treatment liquid W ′. And only nondetermining nuclides such as Fe and Al are precipitated as hydroxides. Then, the non-determined nuclide precipitate is removed from the processing liquid W ′ (separate the non-determining nuclide precipitate and the processing liquid W ′ in which the determining nuclide remains), and the non-determining nuclide is recovered from the processing liquid W ′.

  Next, the processing liquid W ′ after the non-determined nuclide recovery step 5a is processed in the determined nuclide recovery step 5b. In this determined nuclide recovery step 5b, sodium hydroxide (sodium hydroxide solution) is added to the treatment liquid W ′ remaining in a state where Co and Eu are dissolved, so that the pH of the treatment liquid becomes 7. Perform sum processing. When neutralization is performed using sodium hydroxide in this way, Co and Eu determined nuclides are precipitated as hydroxides. As a result, a precipitate containing a large amount of hydroxides of Co and Eu and a small amount of non-determined nuclide hydroxides such as Fe and Al is produced. By collecting the precipitate from the processing liquid W ′, Compared with the conventional method for treating activated concrete, the volume-reduced precipitate containing Co and Eu determinate nuclides is recovered.

  On the other hand, in the method for treating activated concrete according to the present embodiment, finely before the nondetermined nuclide recovery step 5a is performed on the treatment liquid W ′ from which the pulverized product S2 ′ has been separated (ie, before the neutralization treatment). The ground material (group of fine ground materials) S1 is charged. In this way, by adding the finely pulverized product S1 to the treatment liquid W ′ before the non-determined nuclide recovery step 5a, the particle size of the finely pulverized product S1 is smaller than 0.5 mm, so that the finely pulverized product S1 can be pulverized stably and quickly. Co and Eu determinate nuclides are removed from the object S1. Then, after removing the determined nuclides of Co and Eu from the finely pulverized product S1, the non-determined nuclide recovery step 5a and the determined nuclide recovery step 5b are performed, and a precipitate of non-determined nuclides not including the determined nuclide and a large amount of determined nuclides are contained. Collect each precipitate individually. As a result, Co and Eu are removed from the finely pulverized product S1, and the finely pulverized product S1 is surely processed together with the normal pulverized product S2.

  At this time, the finely pulverized product S1 ′, which has been introduced into the treatment liquid W ′ from the pulverization step 2 to the recovery step 5 to remove the determined nuclide, has a small particle size, and therefore a part of the fine pulverization product S1 ′ floats in the treatment liquid W ′. It will be in the state. A part of the finely pulverized product S1 'from which the determined nuclide has been removed is returned to the solid-liquid separation step 4 by decantation (supernatant removal). In addition, the finely pulverized product S1 'after removal of the determined nuclide that is not removed by decantation and remains in the processing liquid W' is recovered together with the non-determined nuclide in the non-determined nuclide recovery step 5a.

  Finally, the solid pulverized product S ′ (S1 ′, S2 ′) obtained in the solid-liquid separation step 4 is dried in the drying step 6 using a dryer, and adjusted to a predetermined moisture content or less. The dried pulverized material S ′ is measured as a radiation dose and confirmed that the determined nuclide has been removed, and then disposed of as general waste, or recycled products such as fine aggregate and coarse aggregate. Shipped as 7. The non-determined nuclide precipitates (including the finely pulverized product S1 ') recovered in the recovery step 5 are also dried and disposed of as general waste or shipped as a recycled product 7. Furthermore, the precipitate containing a large amount of nuclide is disposed as radioactive waste.

  Therefore, in the activation concrete processing method of the present embodiment, the pulverized product S obtained in the pulverization step 2 is grouped for each predetermined particle size range, and the washing step 3 and the solid-liquid separation step 4 for each group. By setting the processing time according to the particle size of the pulverized product S, it becomes possible to perform the processing efficiently. Thereby, compared with the case where the ground material S from which a particle size differs conventionally is processed simultaneously, the time and energy concerning processing can be reduced, and the activated concrete 1 can be processed efficiently and economically. It becomes possible.

  In addition, the recovery process 5 is divided into a non-determined nuclide recovery process 5a and a determined nuclide recovery process 5b, and the treatment liquid W ′ that shows strong acidity by using nitric acid or the like in the washing process 3 is first used for the non-determined nuclide using ammonia water. By performing the neutralization process in the recovery step 5a, it becomes possible to precipitate and recover only non-determined nuclides such as Fe and aluminum Al in the processing liquid W ′ as hydroxides. Then, the treatment liquid W ′ from which the non-determined nuclides have been removed is further neutralized using sodium hydroxide to precipitate Co and Eu determined nuclides remaining in the treatment liquid W ′ as hydroxides. Can be recovered. In this way, the precipitate of nondetermining nuclides and the precipitate containing a large amount of deciding nuclides are separately precipitated and recovered, so that the conventional treatment liquid W ′ is neutralized to simultaneously precipitate the nondetermining nuclides and the determinating nuclides. Compared with the case of collecting in this manner, a precipitate containing a large amount of the determined nuclide can be obtained after the determined nuclide recovery step 5b, and the processing cost can be greatly reduced. Therefore, it becomes possible to process the activated concrete 1 more efficiently and more economically.

  At this time, by neutralizing the treatment liquid W ′ using ammonia water in the non-determined nuclide recovery step 5a and sodium hydroxide in the deterministic nuclide recovery step 5b, the determined nuclide is contained in the treatment liquid in the non-determined nuclide recovery step 5a. The non-determined nuclides can be reliably precipitated and removed as hydroxides, and the determined nuclides remaining in the processing solution W ′ after the non-determined nuclide recovery step 5a are reliably hydroxylated in the determined nuclide recovery step 5b. It becomes possible to precipitate and remove as a product.

  In addition, by introducing the finely pulverized product S1 into the treatment liquid W ′ before the non-determined nuclide recovery step 5a, it becomes possible to remove the determined nuclide from the finely pulverized product S1 in a short time and stably. Then, after removing the determined nuclide from the finely pulverized product S1, the non-determined nuclide recovery step 5a and the determined nuclide recovery step 5b are performed, and the precipitate of the non-determined nuclide that does not include the determined nuclide and the precipitate that contains a large amount of the determined nuclide, respectively. By individually collecting, the finely pulverized product S1 can be reliably processed together with the normal pulverized product S2. Thereby, it becomes possible to process the activated concrete 1 more efficiently and economically.

  As mentioned above, although one Embodiment of the processing method of the activated concrete which concerns on this invention was described, this invention is not limited to said one Embodiment, In the range which does not deviate from the meaning, it can change suitably.

1 Activated concrete (waste concrete block)
2 Crushing process 3 Washing process 4 Solid-liquid separation process 5 Recovery process 5a Non-determined nuclide recovery process 5b Decided nuclide recovery process 6 Drying process 7 Recycled product S Ground product S 'Ground product S1 Finely ground product S1' S2 'Normal ground product W Treatment liquid (cleaning liquid)
W 'Treatment liquid (cleaning liquid)

Claims (4)

A pulverization step of pulverizing the activated concrete, a cleaning step of washing the pulverized product of the activated concrete obtained in the pulverization step with a treatment liquid to remove the determined nuclide from the pulverized product, and a pulverized product after the cleaning step In a method for treating activated concrete, comprising: a solid-liquid separation step for separating the treatment liquid; and a recovery step for collecting the determined nuclide from the treatment liquid separated in the solid-liquid separation step.
The pulverized product obtained in the pulverization step is grouped for each predetermined particle size range,
A method for treating activated concrete, wherein the pulverized material divided into groups is treated by setting treatment times for the washing step and the solid-liquid separation step. In the processing method of the activated concrete of Claim 1,
The recovery step comprises a non-determined nuclide recovery step for precipitating and recovering non-determined nuclides in the treatment liquid, and a determined nuclide recovery step for precipitating and recovering the deterministic nuclides in the treatment liquid after the non-determined nuclide recovery step. A method for treating activated concrete, comprising: In the processing method of activation concrete of Claim 2,
In the non-determined nuclide recovery step, the non-determined nuclide is precipitated by adding ammonia water to the treatment liquid and neutralizing it,
In the determined nuclide recovery step, the determined nuclide is precipitated by adding and neutralizing sodium hydroxide to the treatment liquid. In the processing method of the activated concrete of Claim 2 or Claim 3,
The pulverized product obtained in the pulverization step is grouped into a finely pulverized product of fine particles and a normal pulverized product other than the finely pulverized product,
The normal pulverized product is processed in the washing step and the solid-liquid separation step, and the processing liquid separated from the normal pulverized product is processed into the processing solution in a stage before being processed in the non-determined nuclide recovery step of the recovery step. A method for treating activated concrete, wherein the finely pulverized material is introduced and the determined nuclides are removed from the finely pulverized material.

Images